A sheet wound dressing formed of cross linked keratin. An insoluble, largely Beta keratin fraction from human hair is acidified to a low pH, preferably less than about 3, which partially solubilizes the keratin by weakening hydrogen bonds. The suspension is added to base, such as ammonium hydroxide, forming a slurry. The slurry is cast directly onto a flat surface, allowing the re-formation of cross-links including hydrogen bonds and disulfide bonds. The resulting cross-linked keratin sheet can be used as a sheet wound dressing or as a scaffolding for growth of cells. The insoluble keratin can be derived from human hair which is washed, rinsed, dried, chopped and treated with peracetic acid to break some accessible disulfide linkages. The treated hair is filtered, rinsed, dried, and ground into a keratin powder. The keratin powder is suspended in a mixture of ammonium hydroxide and ammonium thioglycollate and heated sufficiently to dissolve the soluble keratin fraction, followed by cooling and centrifugation to concentrate the insoluble, largely Beta keratin fraction.